This invention relates to a drag reducing device for a marine vessel, and more particularly to a drag reducing device for barges.
Because of the simplistic, bulky, flat design of barges, their movement through the water creates considerable drag. Since it is customary to move multiple numbers of barges through the water at one time, usually in tandem, by a single tow boat, the cumulative effect of the drag created by all of the barges requires considerable power, not only to force the water away from the path of each barge, but also to overcome the total drag created by all of the barges.
Drag reducing devices for marine vessels, of a type which directs air from the atmosphere to areas beneath and alongside the vessel to reduce friction, are known in the art, as illustrated in the following U.S. Pat. Nos.:
______________________________________ 312,500 Owen Feb. 17, 1885 955,703 Settergren Apr. 19, 1910 1,398,246 Trask Nov. 29, 1921 1,591,748 Dieckmann Jul. 6, 1926 1,621,625 Casey Mar. 22, 1927 2,378,822 Barry Jun. 19, 1945 2,727,486 Dunning Dec. 20, 1955 3,084,651 Parmenter Apr. 9, 1963 ______________________________________
All of the above patents, except the Dieckmann patent, disclose the discharge of air along the surface of the hull of the boat. The Dieckmann patent discloses the discharge of water along the sides of a boat.
The Parmenter U.S. Pat. No. 3,084,651 discharges air beneath the hull of the boat primarily for the purpose of reducing the sound energy transmitted from the vessel to the surrounding water.
The Owen, Settergren, Barry and Dunning patents disclose devices receiving air from the atmosphere as the boat moves through the water, and conveying the air below the water surface and along the hull surface, to reduce the frictional resistance of the water along the surface of the hull, and/or to reduce the vacuum created by the movement of the hull through the water.
The Casey U.S. Pat. No. 1,621,625 discloses a plurality of air conduits extending substantially parallel along the bottom of a flat-bottom vessel, or barge, to provide an air sheet between the water and the hull surface to reduce water friction, and also to provide some forward propulsion for the barge.
However, none of the above patents disclose a drag reducing device including air passages from the atmosphere to areas beneath the vessel, which is freely suspended for swinging beneath a trailing vessel or barge connected in a tandem of barges, when the barges are moving through a body of water.